Apparatus for burning pulverized fuel



May 21, 1929.

G. H.-KAEMMERLING 1314.

APPARATUS FOR BURNING PULVERIZED FUEL 2 Sheets-Sheet 1 Filed Aug. 19, 1925 L E-L 4 INVE NTOR 6.19, KAEMMERL/NG. BY Q M;

' mm 24 AT T ORNE Y$ May 21, 1929. G. H. KAEMMERLING APPARATUS FOR BURNING PULVERIZED FUEL Filed Aug. 19, 1925 2 Sheets-Sheet 2 .INV NTOR GHKAEMMERLING.

k ATTORNEYS.

Patented May 21, 1929.

UNITED STATES, PATENT OFFICE,

GUSTAV HENRY KAEMMERLING, 0F ALLENTOWN, PENNSYLVANIA, ASSIGNOR, BY MESNE ASSIGNMENTS, TO FULLER LEKIG H COMPANY, A CORPORATION OF DELA- WARE.

APPARATUS, FOR BURNING ronjvnnrznn FUEL.-

Application filed August 19,1925. Serial No. 51,167fi This invention relates topulverized fuel furnaces and more particularly to a pulverized through one or more of the side walls of a furnace. In accordance with the vertical method of firing a mixture of fuel and air is admitted through the burners and passes downwardly closely adjacent to the front wall of the furnace where ignition takes place by the heat radiated from the furnace wall. The

a descending fuel and flame stream, as combustion proceeds, expands, reverses upon itself and passes upwardly to a boiler in a continuous and uninterrupted stream with very little turbulence or agitation. In order to accommodate this longflame and to provide an air space beneath it through which the noncombustibles are precipitated and cooled below the fusing point and are depositedupon the floor of the furnace, the height of the furnace must necessarily beexcessive. s i In this type of furnace'ignition 1s dependent upon radiant heat from the front wall and the returned flame, and the,process of combustion is necessarily delayed by lack of adequate mixture of the fuel and air which becomes more'involved as combustion proceeds and gaseous products of combustion surround the fuel stream and delay the reaction of the incoming air upon the unburned carbon,

As: iswell known, radiant heat penetrates only the surface of the pulverized fuel stream and as the inner portion of the stream is effectively blanketed, the. process of combustion is further delayed.

' In accordance with,the horizontal method" of firing, the injected fucl and air stream, as combustion proceeds, expands and passes upwardly at an angle of approximately 90 de-' grees. A similar space below-the flame is also provided with this method to prevent slagging "of the ash, and although the capacity of the combustion chamber is less than that nee-- essary for vertical firing, many of the same disadvantages obtain during the process of a combustion. The horizontal flame is shorter than the vertical flame because this designlends itself more readily to the use of a mul-' tiplicit-y of burners whereby the jets may be much reduced in size and inertia. Turbulence exists in some small degree but because the heat radiated from the front wall does not impinge directly upon the fuel and flame horizontally fired furnaces have their best application in connection with the combustion of high volatile fuels? An ideal combustion condition would be one in which the fuel to be burned would enter the furnace in mixture with its full quota of air for combustion and in which the air and fuel would be maintained in a highly turbulent or agitated condition dur- '65 streams after the manner of vertical firing,

ingthe process of combustion. As jet velocity is an important factor in obtaining turbu-.

lence, it will be quite apparent that in the horizontal and vertical methods of firing turbulence is greatly restricted, as the jet velocities must be quite ,low to prevent impingement of the flame stream upon the walls or floor of the furnace with ther resultant destruction of the refractories and the deposition of slag.

The present invention, whichis an adaptation of that disclosed in my co-pending application, Serial No. 67 3,076, filed November 6th, 1923, is intended to provide a. furnace of small combustion chamber capacity as com; pared with the pulverized fuel furnaces of the prior art, in which ignition and combustion take place independently of heat radiated from the walls of the furnace, in a manner to be described in detail hereinafter, in which it is possible-to burn much greater quantities of fuel at higher efficiencies and with greater and maintenance cost, and in which high jet velocities are employed to create a combustion zone of very high'turbulence in which the incoming fuel and the combustion air flexibility of boiler, ratings with'low initial are brought into immediate and violent agitation. In accordance with my invention, the

economical advantages resulting from the combustion of pulverized fuel may be obtained in a furnace having considerably less combustion chamber capacity than the usual type of stoker fired furnace. A further ad vantage of the present invention exists in the provision of a combustion zone within a furnace remote from the furnace walls, the positlon and shape of whlch can be controlled,

and similar to my previous invention, having a vertlcal velocity'very much lower than pul intercepted by the jet issuing from the next burner on one side and intercepts the jet issuing from the next burner on theother side. The number of jets employed should not be less than four and the preferred arrangement consists of five burners'positioned at equal intervals around an imaginary circle on thefloor of the'furnace.

In the preferred arrangement, jets issuing from the several burners are in the form of a flat ribbon of narrow cross-section and are projected from the-orifices at high velocity. The impinging jet having decreased somewhat in velocity is diverted from its path by the next adjacent jet and this process is v repeated throughout the circle. The veloci: ties are such that the resultant effect is to 1 air from the next adjacent burner and bycreate a rapidly moving mass of fuel and air in which the particles are subject to violent turbulence and agitation,

Ignition takes place by the action of a flam ing jet impinging on the incoming fuel and radiation from the central flaming mass. By

' this means I create a self-supporting and selfsustaining combustion zone wholly independent of refractory walls for support or confinement. I

The entire volume be admitted with the fuel, but I prefer to admit a portion of the combustion air as, secondary air, in order to cool. the Walls of the combustion chamber, to obtain the advantages of preheated combustion air, and to permit the use .of smaller diameter blast piping in connection with the burning equipment.

' I prefer to admit the secondaryair at or near the inwardly the bottom of the combustion. chamber in such manner that this relatively cool air will be direc'ted inwardly and will converge toward and below the combustion zone whereby the floor of the furnace will be protected by movingblanket of air. The secondary air thus admitted below the combusof Fig. 4.

Y projecting through of combustion air ma tion zone, assists inthe normal tendency of the products of combustion to rise toward the heat absorbing surfaces of the boiler. As will beapparent,-the direction and volume serve to control the position and shape of thezone.

. The further objects and advantages of my invention will be apparent from the following detailed specification and the claims appended thereto.

4 With reference ings,

Fig. 1 is a sectional elevation through a pulverized fuel furnace embodying my into the accompanying drawvention.

Fig. 2 is a detail plan view illustrating the arrangement of water andfuel-air connections.

Fig. 3 is a detail plan view on line A-A Fig. i is an enlarged sectional elevation of the burner arrangement shown in Fig. 1. In the drawings a pulverized fuel boiler furnace embodying my invention is shown at 10 having a front wall 11, side wall 12, rear wall 13 and floor 14. The horizontal dimensions of the walls ofthe furnace are such as to accommodate a conventional type of boiler as that indicated at 15 positioned immediately above the combustion chamber 16.

Positioned preferably in the center of and the floor of the combustion chamber are a plurality of burners 17 in this instance five, and preferably not less than four. Referring particularly to Figs.

3 and 4, each burner 17 comprises a hollow casting with a double wall to provlde a space 18 for the circulation of cooling water and a hollow cylindrical portion 19 through which the mixture of fuel and primary air is in ected. This mixture issues from an elongated flat orifice 20 provided near the upper portion and extending through both walls of the burner.

The inner wall of the burner casting extends upwardly beyond the orifice as at 21 and is curved as shown, in order that the issulng jet of fuel and air will be in the form of a ribbonand will consist of a uniform mixture. The direction of the issuing jets of fuel and air is indicated by the arrows in Fig. 3 and is such that each jet impinges upon the next adjacent at apoint of high velocity of the latter, whereby the inertia of the second jet will divert the first, so that a zone of high tu'rbu-.

lence is created in which the fuel and air are intimately mixed. With this arrangement each jet is ignited because of the impingement upon it of thejet issuing from the burnq are connected. The tubes38curve er at one side and in turn serves to ignite-the jet issuing from the burner on the other side.

Thus the fuel and airinixture issuing from the several jet-s is diverted toward the center of the circle about which the burners are placed and the mingled'fuel and airis consumed ina central, self-defined flaming mass. Dueto the very high degree'of agitation and turbulence, combustion proceeds very rapidly and accordingly'laige quantities of fuel are consumed Within a relatively small space, which permits the horizontal dimensions of the furnace to be restricted to those necessary to accommodate a conventional type of boiler.

The burner slots 20 are preferably of narrow rectangular cross-section as shown, rather than circular, in order that the issuing jet may be confined to a narrow rectangular'cross-section. This form of jet is more easily diverted and acts more effectively as a confining wall to the combustion zone, as its momentum is less,

anditis more rapidly acted upon by the remaining jets.

Pulverized coal is withdrawn from a bin 22 by conventional feeders 23 which discharge through pipes 24 into mixing Ts 25 in the path of primary air coming from the fan 26 and through the air header 27 The mixture of fuel and air is projected through the pipes 28 into a mixing chambef 29, having a deflector 30 which aids in maintaining a uniform mixture of coal and air and serves to distribute substantially equal quantities of fuel and air through the outlets 31leading to the various burners 17.

Connected at or near the bottom of the boiler drum 32 is a downcomer 33 which serves to conduct cooling water to a circular header 34 provided with outlets 35 suitably flanged, as at 36, to the burner castings 17in such manner that the water may be circulated upwardly through the hollow passageways 18. A water' discharge orifice is provided at 37 in the upper end of each burner to which tubes 38 upwardly and outwardly as indicated in Fig. 2, 'pass through the walls of the combustion chamber and terminate in headers 39 and 40 adjacent to the front and rear walls, respectively.

Return circulation to the boiler is provided through tubes 41 and 42 which terminate in the boiler drum 32 approximately at. Water level. By this means a continuous fiow of wateris provided through the burners, serving to cool the latter, and as the burner castings and the connecting piping 38 are exposed in a zone of high temperature, a high transfer of heat to this portion of the circula- 3 tory system of the boiler will result. It will be noted that adequate cooling means is provided for the burning equipment and that in the arrangement shown relatively little tubing is required.

The combustion chamber 16 is entirely surrounded by hollow wallswhich comprise a plurality of vertical independent air passageways 45. At the top of each passageway 45 anopening 46 leading through the outer wall is provided through which air under the control of dampers 46" may be admitted and which will descend through the passageways, absorb heat from the inner surface of the hollow wall to cool the latter, and pass into the combustion chamber through openings 47 situated near the floor of the furnace. Theair entering through the apertures 47 .moves inwardly and blankets the floor and prevents disintegration, due to the high temperature which would otherwise exist at this point.

The inwardly moving air converges toward the burners and moves below the combustion zone where, due to the turbulent efiect of-the jets, this preheated secondary air will mix violently with the unburned combustible material and will serve both to control and confine the flame and assist the normal. tendency of the products of combustion to rise toward the boiler.

As the flame rises within the furnace it expands as a compact inverted cone and presents a relatively large surface from which radiant heat is directed to the lowermost tubes of the boiler. The boiler is suitably baffled as indicated at 5O and 57 the battles being so constructed that at least one, and preferably more than one, bank of tubes may be exposed to the radiant heat of theflame. After passing through the boiler, the waste gases are passed through the usual outlet fiue 52.-

It will be apparent from-the foregoing de- 100 scription that by applying the principles of the present invention, pulverized fuel furnaces may be erected at low costand operated at high ratings and efliciencies,='thereby making the economies incident to pulverized fuel firing commercially practicable in all types of installations and of particular importance and without materially changing the boiler settings. The favorable radiating conditions and the shape and position of the flame are such'that the furnace may be operated for considerableperiods withoutrepairs and at an I claim: 1 j v 1. In apparatus for burning pulverized fuel, a plurality of burners arranged at substantially equal intervals about an imaginary circle, each burner having a discharge orifice' ofnarrow rectangular cross-section, the longer sides of the rectangle being per pendicularto the plane of the circle, each discharge orifice directed inwardly to project a-"jet of air and fuel to impinge upon an adjacent jet and to be diverted thereby.

extremely low maintenance cost.

2. A furnace for burning pulverized fuel which comprises a combustion chamber, a plurality of burners arranged in series about a circle within the combustion chamber and remote from the side walls of the latter, each burner having a discharge orifice directed inwardly to intersectthe said circle and to project a jet of fuel and air to impinge upon the adjacent jet-at one side to be diverted thereby and to be impinged uponby the adjacent jet at the other side to divert the latter.

3. A furnace for "burning pulverized fuel,

comprising a combustion chamber and a plurality of burners arranged about a substantially horizontal circle within and remote from the walls of this chamber, these burners having discharge orifices of elongated rectangular cross section extending vertically and lying with their horizontal axes substantially in a plane,-each burner being arranged to project a mixed jet of fuel and air which intercepts the jet issuing from the adjacent burner at one side thereof and is in turn intercepted by the jet issuing from the burner at the other side thereof, whereby the jets of fuel and air are diverted inwardly to-.

ward the center of the circle and the fuel is burned in a zone in which violent agitation is continuously maintained.

4. A furnace for burning pulverized fuel comprising the combination of a combustion chamber, a plurality of burners arranged at substantially equal intervals about a circle and remote from the walls and floor of the chamber each burner having a discharge s orifice of elongated rectangular cross-section, these discharge orifices extending substanto project a jet of fuel and air inwardly in bounded by the jets.

tially parallel and each orifice being arranged such manner as to impin e upon the jet issuing from the adjacent urner at one side thereof and to intercept the jet issuing from the next adjacent burner at the other side thereof, whereby a. rapidly moving turbulent combustion zone is maintained which is 5. A furnace for burning pulverized fuel which com rises a combustion chamber, a plurality of urner tubes arranged at substantially equal intervals about a circle at a .dis-

tance from the side walls of the combustion chamber and projecting perpendicularly throu h the floor of the combustion chamber, each urner having a discharge orifice directed inwardly at an angle to a radius of the circle, and the orifices lying with their horizontal axes substantially in a plane and at a distance above the floor of the combustion chamber, the burners projecting ets of fuel and air in'such manner that the et issuing from each burner impingesupon the 'et issuing from the burner at one side thereof and is diverted thereby and is in turn 1minged upon by the jet issuing from the urner at the other side thereof, the diversion of the jets causing the flaming streams therefrom to mingle in a common central flaming mass.

6. A furnace for burning pulverized fuel which comprises a combustion chamber, a plurality of burners arranged at substantial- 1y equal intervals about a circle within the combustion chamber and remote from the side walls of the latter, each burner having a discharge orifice directed to project a jet of fuel and air which impinges upon the jet issuing from the burner at one side thereof and is impinged upon by the jet issuing from the burner at the other side thereof, and means for admitting additional air near the bottom of the combustion chamber.

7. A furnace for burning pulverized fuel which comprises a combustion chamber, a plu rality of burners arranged at substantially equal intervals about a circle within the combustion chamber and remote from the side .walls of the latter, each burner having a disthrough the said side walls inwardly an toward the combustion zone created by the burners.

8. A furnace for burning pulverized fuel which comprises a combustion chamber, a-

plurality of burners arranged at substantially equal intervals about a circle within the combustion chamber and remote from the side walls of the latter, each burner having a discharge qrifice arranged to project a jet of fuel and air which impinges upon the jet issuing from the adjacent burner at one side thereof and is impinged upon by the jet issuing from the burner at the other side thereof, and

, means for admitting additional airfor' com- 7 bustion near the bottom of the chamber, this additional air flowing over the floor thereof and convergin below the combustion zone created by the urners.

9. A furnace for burning pulverized fuel which comprises a combustion chamber, a

luralitv of burners arranged at substantialy equal intervals about a circle within the combustion chamber and remote from the side walls of the latter, each burner having a discharge orifice directed inwardly to project a jet of fuel and air which impinges upon the jet issuing from the burner at one side there-' of and is impinged upon by the jet issuing from the burner at the other side thereof, T

air passageways in'the walls of the combustion chamber having outlets near the bottom of the chamber through which the additionl air for combustion may enter the chamber created I 5 plurality of barriers arranged at substantially equal intervals about a circle within the combustion chamber and" remote from the side walls of the latter, each burner having a discharge orifice directedinwardly to pro.- ject a jet of fuel and air which impinges upon the jet issuing,from the burner at one side thereof and is impinged upon by the jet issuing from the burner at the other side thereof, air passageways in the side walls of the furnace, means for admitting air into the passageways under control, and outlets for the air into the combustion chamber through which .air is discharged to converge upon the I combustion zone created by the burners.

11. A furnace for burning pulverized fuel which comprises a combustion chamber, a plurality of upright burners extending above the floor of the chamber and spaced inwardly from the walls thereof, these burners being arranged substantially in a circleand each burner having a discharge orifice through which a jet of fuel and \air is projected in such manner that the jet issuing from each burner intercepts the jet issuing from the burner adjacent to it and on one side'thereof and is intercepted by the ct issuing from the adjacent burner at the other side, thereof, passageways in the burners, means for cause ing a flow of cooling medium through'the. passageways, and means for supplying fuel and air mixture to the burners.

12. A furnace for burning pulverizedfuel which comprises a combustion chamber, a.

' plurality of upright burners extending above the floor of'the chamber and spaced inwardly from the walls thereof, these burners being arranged substantially in a circle and each burner having a discharge orifice through which a jet of fuel and air is projected in such manner that the jet issuingfrom each burner intercepts the jet issuing from the burner adjacent to it andon one side thereof,

and is intercepted by the jet issuingfrom the adjacent burner at the other side thereof, a distributing device connected to all of the burners, and means for delivering fueland air mixture=to the distributing device.

- 13. A furnace-for burning pulverized fuel which com rises a combustion chamber, a

plurality o upright burners extending above the fioor of the chamber and spaced inwardly fromvthe walls thereof, these burners being arranged substantially in a circle and each burner having a discharge orifice through which a jet of fuel and air is projectednin burner intercepts the jet issuing from the burner adjacent to it and on one side thereof, andis intercepted by the jet issuing from the adjacent burner at the other side thereof,

passageways in the burners for the flow of a cooling medium, and pipes connected with the burners and extending in' proximity to the combustion zone created by the burners for carrying off the cooling medium from the burners.

14. A furnace for burning pulverized fuel which comprises a combustion chamber, a plurahty of upright burners extendmg above the "floor of the chamber and spaced inwardly from the walls thereof, these burners being arranged substantially in a circle and each burner having a discharge orifice through which ajet of fuel and air' is projected in such manner that thejet issuing from each burner intercepts the jet issuing from the,

burner adjacent to it and on one side thereof and is intercepted by .the jet issuing from the adjacent burner at the other side thereof, and means for passing a cooling medium through the burners and in proximity to the combustion zone created by the burners.

15. A furnace for burning pulverized fuel which comprises a combustion chamber, a plurality of burners extending above the floor of the chamber and spaced inwardly from the walls thereof, these burners being arranged substantially in a circle and each burner having a discharge orifice through which a jet of fuel and air is projected in such; manner that the jet issuing from each burner intercepts the jet issuing from the burner adjacent to it and one one side thereof, and is intercepted by the j et issuing from the adj acent burner at the other side thereof, means for supplying a cooling medium to the burners, and pipes for carrying away the cooling medium extending through the combustion chamber in proximity to the combustion zone created by the burners and passing out of the chamber through the walls thereof.

16. A furnace installation for burning pu1;-

verized fuel'which comprises a combustion, chamber having an outlet, a boiler havingv heat-absorbing surfaces supported in communication with the said outlet, a plurality each burner having an orifice arranged to direct-a jet-0f fuel and air inwardlyto be intercepted by the jet issuing from the next adjacent burner at one side and to intercept the jet issuing from the next adjacent burner at the other side, passageways in the burners,

and means connectedto the circulating system of the boiler for causing a flow of water through the burners.

. 17. A furnace installation for burning pulverized fuel which comprises a combustion,

chamber having anoutletgna boilerhaving heat-absorbing surfaces supportedgin communication with the said outlet, a plurality of burners in the combustion chamber ar-. ranged substantially about a circle and spaced burner aving an orifice arranged to direct a jet of fuel and air inwardl to be intercepted by the jetissuing from t e next adjacent 5 burner at one side and to intercept the jet issuing from the next adjacent burner at the other side, passageways in the burners, pipes connected to the passageways and leading from the tops of the burners through the combustion chamber, these pipes being connected to the circulator system of the boiler, and means for suppying water from the said system to the passageways in the burners.

18. A furnace for burning pulverized fuel 1 which comprises a combustion chamber, a

plurality of burners arranged at substanv tiall equal intervals about a circle within the com ustion chamber and remote from the walls of the latter, each burner having a discharge orifice arranged to project a jet of fuel and air inwardly to im inge upon the jet issuing from the adjacent burner at one side thereof and to be impinged upon by the jet issuing from the burner at the other side thereof, a distributing device outside the chamber and disposed centrally with relation to the burners, this device being connected to the burners, and means for supplying a fuel and air mixture to the said device.

In testimony whereof I afiix my signature.

GUSTAV HENRY KAEMMERLING. 

